1. Field of the Invention
This invention pertains to a lubrication system for a transmission or gearbox irrespective of the orientation of the gearbox with respect to gravitational forces and particularly for systems which require high quality lubrication with a limited quantity of lubricant. An eminent example of application of this system is a speed reduction and counter-rotating drive for a torpedo, an application that requires a high quality lubrication of high speed reduction gearing using a minimum of lubricant in a system in which there is no "right side up."
2. Background Art
Gearbox lubrication systems can generally be classified in three groups: those in which lubrication depends on the splash and momentum of lubricants in which parts or all of components of the gear train run immersed in the lubricant; those in which a splash system is enhanced, supplemented or partially replaced by components included for the purpose of lubricant distribution; and those in which an auxiliary or external pump or other device is used to supply lubricant from a separate source under pressure. This invention pertains to the second of those three categories, i.e., that in which lubrication is enhanced by the inherent design of, or use of modified or additional components in, the gear train itself. An early form of lubrication enhancement is represented by Byrne, U.S. Pat. No. 342,425, wherein a rotating member which runs partially submerged in an oil sump has added to it an open-ended pipe or scoop which picks up oil from the sump at each revolution and then permits that oil to gravitate over working parts during another portion of the revolution. Other systems, too numerous to mention, having scoop pickups include Christie, U.S. Pat. No. 3,502,177, which combines an oil scoop pickup on a rotating member with a spinning member which receives the lubricant from the scoop and forces it through a filter element by means of centrifugal force. A modification of this concept is represented by Tholl et al., U.S. Pat. No. 2,754,693, wherein a pitot tube is used in combination with a lubricant flow induced by movement of other parts so that a portion of the flow is diverted by the pitot tube and carried to a position where it is released for gravitational flow over moving parts. A still further refinement is represented by McAfee et al., U.S. Pat. No. 3,065,822, wherein a pitot tube inserted in a rotating supply of lubricant created by centrifugal force imparted by a spinning gear is used to guide oil through passageways to be distributed under the force of the flowing lubricant rather than by means of gravity to portions of a gear train. However, McAfee's gear 33 appears to have been added solely as a lubrication pump and serves no other purpose. A variation of McAffee's system is shown in Rabson, U.S. Pat. No. 2,980,209, where a deflector is used in combination with a hole in a surface as an oil flow pickup to feed oil to a tube for movement to an element to be lubricated. As an added feature, Rabson includes holes in the spinning member which induces the flow of lubricant to enhance and direct oil flow, but, like McAfee, Rabson uses gravity for return of the lubricant to an operating sump. Pitot tubes or rotating casing pumps are also treated in the "Pump Handbook," I. J. Karassik (and others), McGraw-Hill, Inc., 1976, wherein pages 2-203 and 2-204 include a characterization of one model, citing a small capacity and medium to low efficiencies.